Grignard reagent

Grignard reagent
any of the group of reagents produced by the interaction of magnesium and an organic halide, usually in the presence of an ether, and having the general formula RMgX, where R is an organic group and X is a halogen: used in the Grignard reaction.
[1900-05; see V. GRIGNARD]

* * *

 any of numerous organic derivatives of magnesium (Mg) commonly represented by the general formula RMgX (in which R is a hydrocarbon radical: CH3, C2H5, C6H5, etc.; and X is a halogen (halogen element) atom, usually chlorine, bromine, or iodine). They are called Grignard reagents after their discoverer, French chemist Victor Grignard (Grignard, Victor), who was a corecipient of the 1912 Nobel Prize for Chemistry for this work.

      Grignard reagents commonly are prepared by reaction of an organohalogen with magnesium in a nitrogen atmosphere because the reagent is very reactive toward oxygen and moisture. Organohalogens vary greatly in their rates of reaction with magnesium. For example, alkyl iodides generally react very rapidly, whereas most aryl chlorides react very slowly, if at all.

      Their chemical behaviour resembles that of carbanions (carbanion), species that contain a negatively charged carbon. Grignard reagents are strong bases (base) and strong nucleophiles (nucleophile). Thus, the Grignard reagent methylmagnesium bromide (CH3MgBr) behaves as if it were equivalent to the methide ion (CH3).

      Except for hydrocarbons, ethers (ether), and tertiary amines (amine), almost all organic compounds react with Grignard reagents. Many of these reactions are used for synthetic purposes, notably those with carbonyl (carbonyl group) compounds (e.g., aldehydes (aldehyde), ketones (ketone), esters (ester), and acyl chlorides), with epoxides (epoxide), and with halogen compounds of certain metals (metal) (e.g., zinc, cadmium, lead, mercury) to form the alkyl derivatives of those metals.

Francis A. Carey

* * *

Universalium. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Grignard reagent — [grē′nyärd΄] n. [after F. A. V. Grignard (1871 1935), Fr chemist] any of a class of reagents with the general formula RMgX, in which R is an organic radical, esp. an alkyl or aryl, and X is a halogen: these reagents react with a great variety of… …   English World dictionary

  • grignard reagent — noun Usage: usually capitalized G Etymology: after Victor Grignard : any of various compounds of magnesium with an organic radical and a halogen (as ethyl magnesium iodide C2H5MgI) that react readily (as with water, alcohols, amines, acids) in… …   Useful english dictionary

  • Grignard reagent — noun an alkyl or aryl magnesium halide, used in the Grignard reaction to form substituted alcohols; they are formed from alkyl or aryl halides and metallic magnesium …   Wiktionary

  • Grignard reagent — /ˌgrinja riˈeɪdʒənt/ (say .greenyah ree ayjuhnt) noun any of a group of alkyl or aryl magnesium halides which are used in organic synthesis. {named after FAV Grignard, 1871–1935, French organic chemist} …  

  • Grignard reagent (compound) — Grig·nard reagent (compound) (grēn yahrґ) [Franзois Auguste Victor Grignard, French chemist, 1871–1935] see under reagent …   Medical dictionary

  • Grignard reagent — any of several compounds of magnesium with an organic radical and a halogen; these reagents undergo reactions with many substances, producing important products …   Medical dictionary

  • Grignard reaction — The Grignard reaction, named for the French chemist François Auguste Victor Grignard, is an organometallic chemical reaction in which alkyl or aryl magnesium halides (Grignard reagents), which act as nucleophiles, attack electrophilic carbon… …   Wikipedia

  • grignard reaction — (ˈ)grēn|yär(d) noun Usage: usually capitalized G Etymology: after Victor Grignard died 1934 French chemist : the reaction of a Grignard reagent with any of several types of compounds (as an aldehyde, ketone, or ester) to yield any of a variety of …   Useful english dictionary

  • Grignard, Victor — ▪ French chemist in full  François Auguste Victor Grignard  born May 6, 1871, Cherbourg, France died Dec. 13, 1935, Lyon       French chemist and corecipient, with Paul Sabatier (Sabatier, Paul), of the 1912 Nobel Prize for Chemistry for his… …   Universalium

  • Reagent — Reagents, such as sulfur (pictured), are the starting materials that are used in chemical reactions. A reagent is a substance or compound that is added to a system in order to bring about a chemical reaction or is added to see if a reaction… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”